/*
    Copyright (C) 2014-2019 de4dot@gmail.com

    This file is part of dnSpy

    dnSpy is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    dnSpy is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with dnSpy.  If not, see <http://www.gnu.org/licenses/>.
*/

using System;
using dnlib.DotNet;
using dnlib.PE;

namespace dnSpy.AsmEditor.Module {
	static class ModuleUtils {
		public static ModuleDef CreateNetModule(string name, Guid mvid, ClrVersion clrVersion) => CreateModule(name, mvid, clrVersion, ModuleKind.NetModule);

		public static ModuleDef CreateModule(string name, Guid mvid, ClrVersion clrVersion, ModuleKind kind, ModuleDef? existingModule = null) {
			var module = CreateModuleDef(name, mvid, clrVersion, existingModule);
			module.Kind = kind;
			module.Characteristics = Characteristics.Bit32Machine | Characteristics.ExecutableImage;
			if (kind == ModuleKind.Dll || kind == ModuleKind.NetModule)
				module.Characteristics |= Characteristics.Dll;
			module.DllCharacteristics = DllCharacteristics.TerminalServerAware | DllCharacteristics.NoSeh | DllCharacteristics.NxCompat | DllCharacteristics.DynamicBase;
			return module;
		}

		static ModuleDef CreateModuleDef(string name, Guid mvid, ClrVersion clrVersion, ModuleDef? existingModule) {
			var clrValues = ClrVersionValues.GetValues(clrVersion);
			if (clrValues is null)
				throw new ArgumentNullException(nameof(clrVersion));
			ModuleDef module;
			if (existingModule is null)
				module = new ModuleDefUser(name, mvid, clrValues.CorLibRef);
			else {
				module = existingModule;
				module.Name = name;
				module.Mvid = mvid;
				OverwriteAssembly(module.CorLibTypes.AssemblyRef, clrValues.CorLibRef);
			}
			module.UpdateRowId(module);
			module.RuntimeVersion = clrValues.RuntimeVersion;
			module.Cor20HeaderRuntimeVersion = clrValues.Cor20HeaderRuntimeVersion;
			module.TablesHeaderVersion = clrValues.TablesHeaderVersion;
			module.Location = string.Empty;
			return module;
		}

		static void OverwriteAssembly(AssemblyRef dst, AssemblyRef src) {
			dst.Name = src.Name;
			dst.Version = src.Version;
			dst.PublicKeyOrToken = src.PublicKeyOrToken;
			dst.Culture = src.Culture;
			dst.Attributes = src.Attributes;
			dst.Hash = src.Hash;
		}

		public static AssemblyDef AddToNewAssemblyDef(ModuleDef module, ModuleKind moduleKind, out Characteristics characteristics) {
			var asmDef = module.UpdateRowId(new AssemblyDefUser(GetAssemblyName(module)));
			asmDef.Modules.Add(module);
			WriteNewModuleKind(module, moduleKind, out characteristics);
			return asmDef;
		}

		static string GetAssemblyName(ModuleDef module) {
			string name = module.Name;
			if (name.EndsWith(".exe", StringComparison.OrdinalIgnoreCase) || name.EndsWith(".dll", StringComparison.OrdinalIgnoreCase))
				name = name.Substring(0, name.Length - 4);
			else if (name.EndsWith(".netmodule", StringComparison.OrdinalIgnoreCase))
				name = name.Substring(0, name.Length - 10);
			if (!string.IsNullOrWhiteSpace(name))
				return name;
			return module.Name;
		}

		public static void WriteNewModuleKind(ModuleDef module, ModuleKind moduleKind, out Characteristics characteristics) {
			module.Kind = moduleKind;
			characteristics = module.Characteristics;
			module.Characteristics = SaveModule.CharacteristicsHelper.GetCharacteristics(module.Characteristics, moduleKind);
		}
	}
}